<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>何为数据代理</title>
</head>

<body>
    <script>

        let obj1 = { x: 100 };
        let obj2 = { y: 200 };

        //通过obj2代理obj1
        Object.defineProperty(obj2, 'x', {
            get() {
                return obj1.x;
            },
            set(value) {
                return value;
                obj1.x = value
            }
        })
    </script>
</body>

</html>